I would include "However", but change the first sentence slightly so the whole thing looks like this: Although victory had been achieved, Laurana was deeply grieved and outraged by the loss of Sturm and the parting words of Kitiara. However , Sturm's sacrifice helped solidify the Knights of Solamnia into a cohesive unit, and Gunthar became the first grand master of the military order since the Cataclysm. The first sentence as you wrote it is correct as well - it's just a style preference
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